Cited document 1 discloses a production method of 2-amino-2-[2-(4-heptyloxy-3-trifluoromethylphenyl)ethyl]propane-1,3-diol hydrochloride useful as a medicament superior in an immunosuppressive action, a rejection suppressive action and the like.
The production method includes a step of reducing 4-heptyloxy-3-trifluoromethylbenzoic acid (Ia) to 4-heptyloxy-3-trifluoromethylbenzyl alcohol (IIa). However, this step has a problem of low conversion ratio or a problem of production of byproduct (IIa′) resulted by reduction of a trifluoromethyl group along with compound (IIa).

Particularly, since a series of analogues derived from byproduct (IIa′) are difficult to remove in the subsequent steps, the production of a drug substance for pharmaceutical products requested to have high quality requires strict suppression of the production thereof.